Effective information support tools are challenging to design for fast-paced, information rich, and difficult to predict circumstances, particularly when information is fragmented and sources are dispersed. To explore, we conducted a field study on handover and the associated information work, which included 40 visits and 75 hours of observation and interviews with doctors in a metropolitan emergency department (ED). Beyond information exchange, we found that handovers highlight doctors' proactive approach by anticipating information needs, managing uncertainties arising from dynamic information, and developing patient care plans through multiple contingencies. Expanding on the idea of handover as a multifaceted process rather than a single event, we reinforce existing calls for greater flexibility emphasising that the ascertainment of pertinent information is an ongoing, adaptive process. This work demonstrates that deciding what constitutes relevant information is a priori indeterminate when designing information systems and support tools in environments such as EDs. We propose the preservation of specific ‘relativities’ of information—such as uncertainty, particularity, incompleteness, and temporality—in designing information support tools for dynamic, critical and multi-disciplinary work environments.